Prosecutors deny immunity deny with kingpin's son

CHICAGO 
Federal prosecutors are denying U.S. agents have an immunity agreement with a top lieutenant in one of Mexico most powerful cartels and are asking a federal judge not to throw out drug trafficking conspiracy charges against him.

Vicente Zambada is being held in Chicago awaiting trial. His attorneys contend he and other cartel leaders were granted immunity by U.S. agents in exchange for intelligence about rival cartels engaged in bloody turf wars in Mexico. They have asked a judge to dismiss the charges against Zambada.

In a response filed electronically late Friday with the U.S. District Court in Chicago, prosecutors flatly deny an immunity agreement exists.

Prosecutors acknowledge Drug Enforcement Administration Agents met with Zambada before his arrest. However, they say agents never entered into an immunity agreement with him.